It is believed that examples of known fuel injection systems use an injector to dispense a quantity of fuel that is to be combusted in an internal combustion engine. It is also believed that the quantity of fuel that is dispensed is varied in accordance with a number of engine parameters such as engine speed, engine load, engine emissions, etc.
It is believed that examples of known electronic fuel injection systems monitor at least one of the engine parameters and electrically operate the injector to dispense the fuel. It is believed that examples of known injectors use electromagnetic coils, piezoelectric elements, or magnetostrictive materials to actuate a valve.
It is believed that examples of known valves for injectors include a closure member that is movable with respect to a seat. Fuel flow through the injector is believed to be prohibited when the closure member sealingly contacts the seat, and fuel flow through the injector is believed to be permitted when the closure member is separated from the seat.
It is believed that examples of known injectors include a spring providing a force biasing the closure member toward the seat. It is also believed that this biasing force is adjustable in order to set the dynamic properties of the closure member movement with respect to the seat.
It is further believed that examples of known injectors include a filter for separating particles from the fuel flow, and include a seal at a connection of the injector to a fuel source.
It is believed that such examples of the known injectors have a number of disadvantages.
It is believed that examples of known injectors must be assembled entirely in an environment that is substantially free of contaminants. It is also believed that examples of known injectors can only be tested after final assembly has been completed.
According to the present invention, a fuel injector can comprise a plurality of modules, each of which can be independently assembled and tested. According to one embodiment of the present invention, the modules can comprise a fluid handling subassembly and an electrical subassembly. These subassemblies can be subsequently assembled to provide a fuel injector according to the present invention.
The present invention provides a fuel injector for use with an internal combustion engine. The fuel injector comprises a valve group subassembly and a coil group subassembly. The valve group subassembly includes a tube assembly having a longitudinal axis extending between a first end and a second end, the tube assembly including a magnetic pole piece having a first face having a first surface area; a seat secured at the second end of the tube assembly, the seat defining an opening; an armature assembly disposed within the tube assembly, the armature assembly having a second face disposed from the first face by a gap, the second face having a second surface area smaller than the first surface area; a member biasing the armature assembly toward the seat; an adjusting tube located in the tube assembly, the adjusting tube engaging the member and adjusting a biasing force of the member; a filter located at the first end of the tube assembly, the filter having retaining portion; an O-ring circumscribing the first end of the tube assembly, the retaining portion of the filter maintaining the O-ring proximate the first end of the tube assembly; and a first attaching portion. The coil group subassembly includes a solenoid coil operable to displace the armature assembly with respect to the seat; and a second attachment portion fixedly connected to the first attachment portion.
The present invention further provides a fuel injector for use with an internal combustion engine. The fuel injector comprises a valve group subassembly and a coil group subassembly. The valve group subassembly includes a tube assembly having a longitudinal axis extending between a first end and a second end. The tube assembly includes an inlet tube, a non-magnetic shell, and a valve body. The inlet tube having a first inlet tube end and a second inlet tube end having a first face having a first surface area. The non-magnetic shell having a first shell end connected to the second inlet tube end at a first connection and further having a second shell end; and a valve body having a first valve body end connected to the second shell end at a second connection and further having a second valve body end. A seat defining an opening is secured at the second end of the tube assembly. An armature assembly and an adjusting tube are disposed within the tube assembly. The armature assembly includes a first armature assembly end having a magnetic portion and a second face disposed from the first face by a gap, the second face having a second surface area smaller than the first surface area; and a second armature assembly end having a sealing portion; a member biasing the armature assembly toward the seat; an adjusting tube located in the tube assembly, the adjusting tube engaging the member and adjusting a biasing force of the member. A filter, which has a retaining portion, is located at the first end of the tube assembly. An O-ring circumscribes the first end of the tube assembly, the retaining portion of the filter maintaining the O-ring proximate the first end of the tube assembly. The valve group subassembly also comprises a first attachment portion. The coil group subassembly includes a solenoid coil operable to displace the armature assembly with respect to the seat, and a second attachment portion fixedly connected to the first attachment portion.
The present invention also provides for a method of assembling a fuel injector. The method comprises providing a valve group subassembly, providing a coil group subassembly, and inserting the valve group subassembly into the coil group subassembly. The valve group subassembly includes a tube assembly having a longitudinal axis extending between a first end and a second end. The tube assembly includes a magnetic pole piece having a first face having a first surface area. A seat, defining an opening, is secured at the second end of the tube assembly. An armature assembly disposed within the tube assembly, the armature assembly having a second face disposed from the first face by a gap, the second face having a second surface area smaller than the first surface area; a member biasing the armature assembly toward the seat; an adjusting tube located in the tube assembly, the adjusting tube engaging the member and adjusting a biasing force of the member; a filter located at the first end of the tube assembly, the filter having retaining portion; an O-ring circumscribing the first end of the tube assembly, the retaining portion of the filter maintaining the O-ring proximate the first end of the tube assembly; and a first attaching portion. The coil group subassembly includes a solenoid coil operable to displace the armature assembly with respect to the seat; and a second attachment portion.